And there's his opponent Angela Merkel - the German Chancellor, the unchallenged leader of Europe. She's relaxed, talking over the journalists who are trying to steer her into controversy, occasionally chopping her hand down for emphasis.

Steinbrueck is on the attack. He accuses Merkel of dithering, of wasting four years with the gearstick in neutral, of laying waste to southern Europe with wait-and-see austerity plans instead of grasping the nettle of serious structural reform.

The leadership of Germany - and so, by proxy, of Europe - is at a standstill, he says. We should take action.

Calmly, Merkel fires back. "I do not act first and then think. I do the reverse. I think, then I decide, and then I act."

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And this, in a nutshell, is why this former research scientist, this empirical mind who measures and analyses the forces that stress the continent, is very, very short odds to win this weekend's election.

But it is also the source of growing frustration, among her natural allies as well as her enemies, who believe she is spending far too much time thinking and deciding.

As Europe tries to stagger back to its feet the debate is intensifying: is now really the time for calm, steady-as-she goes politics? Or is this one of those rare moments in the political cycle where someone has the influence, the experience and the political capital to make bold changes that will cure, rather than just balm, Europe's economic sickness? And if anyone can play that role, it must be Merkel's Germany.

A quick sample of the posters tied to lampposts around Berlin suggests the issues that matter to the locals. "Fair wages", say the Greens, promoting their plan for a living wage. "Old age without poverty" cries the SPD [Steinbrueck's Social Democratic Party, the main opposition to Merkel's CDU, or Christian Democratic Union]. The CDU's posters show Merkel's phlegmatic face and promise economic growth and a stable euro. "Jobs", they proclaim. "Families".

German elections are complicated. The eccentric voting system almost ensures no party can win a majority, so coalitions dominate. In 2005, Steinbrueck was finance minister in Merkel's cabinet in a ''grand coalition'' of left and right.

Since 2009 the coalition junior partner has been the pro-business Free Democrats (FDP). But endless infighting, and an inability to get any of its policies past Merkel's veto, has seen its vote collapse.

Another complication could come from Germany's newborn anti-Europe movement. In April a group of academics formed the Alternative for Germany party, quickly dubbed the ''professors' party'', which advocated an end to the euro (though not the EU) and the cycle of bailouts and austerity measures that monetary union seems to require. A bourgeois protest party with a distinctly amateur air, it has failed to find much of a following despite stunts such as burning fake 500-euro notes. However, some argue that its actual vote will be far higher than polls suggest, giving it real clout in the post-election coalition talks.

Some voices are saying a new grand coalition would be the best outcome. "Europe would be better off with the stability, depth and breadth of a grand coalition," says one well-connected Berlin political insider. "Tough pro-Europe policies could be effected without the politicking."

It certainly appeals more to the average German than a ''red-red-green'' coalition of the centre and radical left or a CDU-Green alliance, the next options on the table.

But there are hidden traps. Last time, the SPD lost millions of votes for appearing too supine in coalition. This time it could well be a more feisty dance partner. On the other hand, if it is left outside the coalition it may decide that a shift to the left would be politically advantageous: sharpening the internal debate= would make Germany a less sure-footed actor outside its borders.

But most of the public seems just to want more of the same. "Merkel has anaesthetised the electorate," the insider says.

This irritates Markus Feldenkirchen, political commentator at weekly news magazine Der Spiegel. In his office a stone's throw from the Brandenburg Gate, he shakes his head and waves his hands in frustration.

"This is the worst level of engagement in a German election that I have ever witnessed," he says. "There is the general impression that there's nothing really at stake, that the programs of the major parties are so similar that there's no real conflict."

It doesn't just make life hard for a political commentator. Feldenkirchen argues it's bad for the country, and for Europe.

"Merkel is presenting herself as a kind of non-political person," he says. "She is talking to people like a grandmother who is telling anecdotes. She is not concrete on anything, she can talk for an hour without saying what's going to happen in the next four years. She doesn't say 'I have a plan' and she's not fighting for it. She is more happy if there is an opportunity to do nothing.

"This is not healthy for Europe. Her concept is 'let's wait', and every week there is another problem and then we have to solve it. She has never said 'the Europe I want looks like this'. There is only step-by-step management. In years from now we will see that more leadership, some concrete goals, would have been better."

Locally, Merkel's presidential, all-ideas-considered approach has left politics bland and lacking spark, Feldenkirchen says. "Conflict is essential for a vital democracy. She is destroying this necessary rule of our culture."

Feldenkirchen has an unlikely ally at conservative think tank DIW Berlin. There, head of economic policy Ferdinand Fichtner says the German election has already hurt Europe.

"It has been very quiet for the last few months," Fichtner says. "It's not just the financial markets calming down. It is also because policy makers have been quiet about Europe."

Fichtner argues there are several key reforms that are necessary to put the continent on the road to long-term stability. Recently the economic figures have been interpreted positively - but in some countries, only in the sense that they are getting worse more slowly. The continent needs banking reform, to unify the rules on acceptable levels of risk, to set out how a bank can safely go bankrupt without taking a country with it, and to regulate banks' balance sheets. This should prevent new credit bubbles. There has been talk on a central fund to take the role of a ''bad bank''.

There are also arguments for reform to the treaty that binds the EU: whether it should be deeper or changed to a ''core and periphery'' model, whether the continent needs a common foreign and defence policy. "That's all come to a halt," Fichtner says.

Inside Germany there is still a majority consensus in favour of European integration and saving the euro. But German policy-makers don't want to say anything that would scare voters into the arms of fringe anti-Europe parties.

Crossing the bridge from the Reichstag towards old East Germany, a slogan leaps out from a massive billboard - "Welcome to the Low Wage Republic of Germany".

There is a simmering mood in Germany. They have worked hard, tightened their belts and kept salaries low, and their reward has been to bear the risk of Europe's profligate south, which took the credit offered to a united continent and spent it on flash cars and mortgages.

"[Politicians] know they need to avoid the crisis coming up again, but also avoid the German public getting the impression we are doing more than necessary," Fichtner says.

Nevertheless, an abundance of caution could do long-term harm.

"The financial markets are calm - but due to temporary measures. We should take this time that has been bought to create a sustainable set-up.

"It's extremely dangerous that this current situation, when the financial markets give us a chance to create a sustainable foundation for the European area, that we don't take this chance. It's clear we can't forever buy more time.

''It is annoying and dangerous that European politics is basically paralysed."

Over at the Hans Boeckler Foundation, Gustav Horn is one of the country's most respected economists. He believes the utmost priority for a new German government should be a program to stabilise the euro area - through stimulus packages in places like Spain, Greece and Italy, and a more macro framework such as a European Monetary Fund.

Horn also argues there is a need to hurry along. The longer austerity bites in southern Europe, he says, the more resentment will build.

"If they say 'we are fed up with all that, we don't obey the rules any more' then we would have a very serious crisis , maybe the breaking up of the Euro area."

Back at the debate, around Merkel's neck is a necklace in the colours of the German flag. In any other country waving the flag is Politics 101.

In Germany, where nationalism is still a guilty pleasure, it is an unexpectedly bold statement ("a bit unsubtle for Merkel," one political insider complains later).

It is a mark of almost unprecedented political confidence. But the question remains as to whether, as the election results come in, she will find herself willing - or even able - to spend the political capital required to save Europe.